# If the depth of a tree is 3 levels, then what is the Size of the Tree?

Skill/Topic: Tree
A) 8
Explanation: You calculate the size of a tree by using the following formula: size = 2 ^ depth If the depth is 3 levels, then the size is 8, as shown here: 8 = 2 ^ 3

#### shyam

• Jan 27th, 2006

the answer is (2 to power 3)-1

i.e 7

#### bigroast Profile Answers by bigroast

• Mar 4th, 2006

I agree that it would be 7.  Isn't it a Fibonacci sequence?  I also assume it's a binary tree.

#### f2003062 Profile Answers by f2003062

• Oct 31st, 2006

We can not say..!First of all it depends on the type of the tree (Ex:binary Tree)...Even if it is a binary tree we can not define its size using its depth..For example look at the following tree 15 / 13 NULL / 10 14In the above binary Tree the depth of is = 3 but the size is = 4 The NULL node is not considered when we calculating the size of the Tree,right..!

#### durga

• Apr 8th, 2015

but y v should take 2^n or 2^n-1

#### durga

• Apr 8th, 2015

but y v shld use 2^n or 2^n-2 formula only can any one give me the explanation

#### Shubh

• Nov 5th, 2018

ANS 8 is correct, 7 is not listed.